﻿<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>弹性盒模型</title>
<style>
	#main{ width:150px; height:150px; border:1px black solid;  		
		display:flex; }
	.box{ width:50px; height:50px; background:red; 
		margin:auto; }
</style>
</head>
<body>
<div id="main">
	<div class="box"></div>
</div>
</body>
</html>
